Answers (1)
Strong acid or base means it ionizes completely in water. It has nothing to do with concentration or corrosiveness. There are seven strong acids:
Sulfuric
Nitric
Hydrochloric
Chloric
Perchloric
Hydrobromic
Hydroiodic
It's easy to remember the list because there are three of the most common industrial acids, three "chloric" acids, three "hydro" acids, and they all make a clumsy "7" on the periodic table.
There are dozens of strong bases and hundreds of "almost strong" bases.
Vinegar is a weak acid, which means not all the acid ionizes. Only enough to maintain the pH. When you add water, then more acid can ionize to maintain the pH at its normal value.